Electric axles with wheel hub drive are known from the state of the art. Wheel hub drives are usually used in industrial motor vehicles and omnibuses as they have the advantage in comparison with flat-type wheel or beveled wheel drives that the transmission, drive motor, brake and wheel are arranged in the smallest space. Furthermore, chassis without continuous axle shafts are made possible through the use of wheel hub drives.
Usually asynchronous machines which include a stator and a rotor are used as wheel hub drives according to the state of the art. Here the rotor is constructed as a cage rotor and as a rule consists of electrically conductive aluminum which is shaped into the rotor in the form of a die casting. Asynchronous machines are highly used motors which require corresponding cooling due to the high heat development.
In German Patent DE 199 05 539 A1 by the Applicant, an asynchronous machine of the type described at the beginning is described into which a heat exchanger of the coolant used in the asynchronous machine is incorporated for the purpose of optimized cooling.
A great amount of heat is also emitted by the bearings and gearings arranged in the closest space in addition to the electric motor as a source of heat. In addition, a special rim with a larger bolt hole is used, the dissipation of heat into the environment is additionally reduced since, in this case, less space is available for the ventilation holes.
Moreover, the brakes or the brake disks prove to be a significant additional source of heat. Accordingly, situations often arise in which the heat developed cannot be completely given off into the surroundings due to the compact construction, so that problems arise which can negatively influence the function and lifetime of a wheel hub drive.
The present invention is based on the objective of representing an axle with wheel hub drive through which the disadvantages of the state of the art mentioned are avoided. In particular, an optimal cooling of the wheel hub drive should be guaranteed.